volume/main.c

This is an example of how to use the ASX Volume functions.

/* $Header: /home/eliot/asi/repo/cvsrepo/Repository/apps/asx/examples/volume/main.c,v 1.2 2010/06/22 18:15:12 as-age Exp $ */
#include "stdio.h"
#include "stdlib.h"
#include "asx.h"
#include "asxstring.h"

ASX_HANDLE hSystem=0;

int CheckError(ASX_HANDLE hObj, const int nLine);
void PrintControlName(ASX_HANDLE hControl);

int main(int argc, char* argv[])
{
    ASX_HANDLE hAdapter;
    ASX_HANDLE hMixer;
    ASX_HANDLE hVolume;
    int nAdapterToUse=0;
    char szName[ASX_SHORT_STRING];
    int nLength;
    int nVol;
    float fGain[2];
    float fMin,fMax,fStep;
    int nChannels;

    // create the system
    ASX_System_Create(ASX_SYSTEM_TYPE_HPI,&hSystem);
    CheckError( hSystem, __LINE__);

    // get the adapter
    ASX_System_GetAdapter(hSystem,nAdapterToUse,&hAdapter);
    CheckError( hSystem, __LINE__);

    // get the adapter name
    ASX_Adapter_GetName(hAdapter,szName,sizeof(szName),&nLength);
    CheckError( hAdapter, __LINE__);
    printf("Adapter [%d] is %s \n", nAdapterToUse,szName);

    // get the mixer handle
    ASX_Adapter_GetMixer( hAdapter, &hMixer );
    CheckError( hAdapter, __LINE__);

    // get a volume object
    ASX_Mixer_GetControlByNodeTypeAndIndex(
        hMixer,
        asxNODE_PLAYER,0,   // play object, index 0
        asxNODE_LINE_OUT,0, // line out object, index 0
        asxCONTROL_VOLUME,
        &hVolume);
    CheckError( hMixer, __LINE__);
    // print out control name
    PrintControlName(hVolume);

    ASX_Volume_GetRange( hVolume, &fMin, &fMax, &fStep);
    CheckError( hVolume, __LINE__);
    printf("Volume max %f, min %f, step %f\n",fMax,fMin,fStep);

    printf("Enter a volume to apply. 0 is fullscale, -100 is off.\n>");
    scanf("%d",&nVol);
    printf("Volume set.\n");
    fGain[0] = (float)nVol; // index 0 is the left channel
    fGain[1] = (float)nVol; // index 1 is the right channel

    ASX_Volume_GetChannels( hVolume, &nChannels);
    CheckError( hVolume, __LINE__);

    ASX_Volume_SetGain( hVolume, fGain, nChannels);
    CheckError( hVolume, __LINE__);

    printf("Press ENTER to exit\n");
    getchar();
    ASX_System_Delete(hSystem);
    return 0;
}

void PrintControlName(ASX_HANDLE hControl)
{
    char *pszName;
    int nLen;
    enum asxCONTROL eControl;

    ASX_Control_GetType(hControl, &eControl);
    ASXSTRING_EnumToString(eControl,0,0,&nLen);
    pszName=(char *)malloc(nLen);
    ASXSTRING_EnumToString(eControl,pszName,nLen,&nLen);
    printf("Control : %s\n",pszName);

    free(pszName);
}

int CheckError(ASX_HANDLE hObj, const int nLine)
{
    int nError;
    int asxSubSystemErrorCode=0;
    char *pszAsxErrorString;
    char *pszAsxSubSystemErrorString;
    int nLen1,nLen2;

    ASX_Error_GetLast( hObj, (ASX_ERROR*)&nError, &asxSubSystemErrorCode);
    if(!nError)
        return 0;
    ASX_Error_GetLastString( hObj, 0,0,&nLen1,0,0,&nLen2);
    pszAsxErrorString = (char *)malloc(nLen1);
    pszAsxSubSystemErrorString = (char *)malloc(nLen2);
    ASX_Error_GetLastString( hObj, pszAsxErrorString,nLen1,&nLen1,pszAsxSubSystemErrorString,nLen2,&nLen2);
    printf("Error: #%d, %s - Subsystem Error: #%ld, %s \n",
        nError,
        pszAsxErrorString,
        asxSubSystemErrorCode,
        pszAsxSubSystemErrorString );
    printf("When called from source %s line %d\n",__FILE__,nLine);

    printf("Press ENTER to exit\n");
    getchar();
    free(pszAsxErrorString);
    free(pszAsxSubSystemErrorString);
    ASX_System_Delete(hSystem);
    exit(1);
    return 1;
}